Final answer:
A note to a supplier thanking him for the Christmas card he sent best exemplifies personal communication.
Step-by-step explanation:
The best example of personal communication among the options provided is a note to a supplier thanking him for the Christmas card he sent. Personal communication refers to direct, one-on-one communication between individuals. In this example, the note is a personal expression of gratitude to the supplier, showing that it is a direct and personal form of communication.